1. Field of the Invention
The present invention relates to a person recognition method and apparatus that retrieve personal data based on a taken photographic image.
2. Description Related to the Prior Art
Recently, there is a proposed apparatus that not only detects a person's face from a photograph, but also automatically recognizes who the person is (see U.S. Pat. Nos. 6,608,914 and 6,697,505). In this apparatus, characteristic values of features of the face, including the positions of eyes, nose, mouth and the like, extracted from a photographic image of the person to be recognized are compared with those extracted from a face image of a registrant registered in advance in a registered information holding section (database). Then, the registrant having a highest degree of resemblance is outputted as a recognition result.
Since the person's face ages with time, the above apparatus is so designed as to add the newly taken photographic image to the database as the face image, whenever carrying out person recognition. Also, Japanese Patent Laid-Open Publication No. 2004-54888 discloses a face recognition device in which the registered face image is deleted when getting old and ineffective, based on a lapse of time from the registration into the database, or a lapse of time from the latest recognition.
In a figure recognition device according to Japanese Patent Laid-Open Publication No. 2004-139259, registration data (face image used in recognition) is updated to the newly taken photographic image within a fixed time period from the registration to the database, whenever the person recognition is carried out, in accordance with change of the person's face. After a lapse of the period, the registration data is not updated anymore because the change in the person's face becomes small or negligible. Thus, eliminating the need for the update allows smooth recognition processing.
In any of the above apparatuses, the precision of the person recognition becomes worse, as the face image registered into the database gets old. Thus, the registrant's face image has to be updated on a regular basis.